assume cs:code
;将一段字符串转换成大写
data segment
	db 'conversatoin'
data ends

code segment

start:	mov ax,data
	mov ds,ax
	mov si,0;ds:si指向字符串(批量数据)所在空间的首地址
	
	mov cx,12;cx存放字符串的长度
	call capital
	
	mov ax,4c00h
	int 21h

capital:
	and byte ptr [si],11011111b
	inc si
	loop capital
	ret

code ends
end start
